Find the 2 highest-rated courses from the `courses` collection.

Problem Statement

<p>Find the 2 highest-rated courses from the <code>courses</code> collection.</p>

Examples

Input: courses collection: +-----+----------------+--------+ | _id | title | rating | +-----+----------------+--------+ | 1 | MongoDB 101 | 4.2 | | 2 | React Advanced | 4.8 | | 3 | Node.js Basics | 4.5 | | 4 | CSS Mastery | 3.9 | +-----+----------------+--------+

Output: +-----+----------------+--------+ | _id | title | rating | +-----+----------------+--------+ | 2 | React Advanced | 4.8 | | 3 | Node.js Basics | 4.5 | +-----+----------------+--------+

Explanation: The collection documents are sorted according to the specified field order.

Complexity

Time Complexity: -

Space Complexity: -

Hints

💡 Hint 1: Sort matched documents using .sort({ field: 1 }) for ascending or { field: -1 } for descending. 💡 Hint 2: Chain .sort(...) directly after db.<collection>.find(...) and before .limit() / .toArray(). 💡 Hint 3: Complete: return db.<collection>.find(<filter>).sort(<sortObj>).toArray();

Editorial & Approach

Problem Overview & Intuition

To solve "Top N Pattern (Sort + Limit)", we query the MongoDB document store. The goal is to find the 2 highest-rated courses from the `courses` collection. Using a targeted find query, the database engine filters and structures the BSON documents efficiently.

Step-by-Step Approach

Identify Target Collection: Access the collection through the db instance.
Construct Query / Pipeline: Build the query filter with appropriate comparison operators.
Resolve Cursor: Invoke .toArray() to transform the query cursor into the required array of documents.

Optimal Implementation (MongoDB)

function solve(db) {
  return db.courses.find({}).sort({ rating: -1 }).limit(2).toArray();
}

Complexity Analysis

Time Complexity O(N) collection scan (O(log N) if index is present on filtered fields).

Space Complexity O(K) where K is the number of returned documents in memory.

Key Considerations & Edge Cases

Empty Collections: If no documents match, the query cleanly returns an empty array [].
Missing / NULL Fields: Missing fields in documents are handled safely without throwing runtime exceptions.
Type Coercion: BSON types (ObjectId, Numbers, Strings) are compared strictly according to MongoDB specifications.

Top N Pattern (Sort + Limit)

Easy

Find the 2 highest-rated courses from the courses collection.

Example Scenarios

1Example 1

Input:

courses collection

_id	title	rating
1	MongoDB 101	4.2
2	React Advanced	4.8
3	Node.js Basics	4.5
4	CSS Mastery	3.9

Output:

_id	title	rating
2	React Advanced	4.8
3	Node.js Basics	4.5

Explanation:

The collection documents are sorted according to the specified field order.

MongoDB Editor

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Query Results (JSON)

Run your MongoDB code to see results here.